I think the issue was by ths following , You can do it using dateutil.parser and datetime.datetime.strftime together.
from dateutil.parser import parse as dtparse
from datetime import datetime as dt
start = '2018-12-26T10:00:00+01:00' # Let's say your start value returns this as 'str'
tmfmt = '%d %B, %H:%M %p' # Gives you date-time in the format '26 December, 10:00 AM' as you mentioned
# now use the dtparse to read your event start time and dt.strftime to format it
stime = dt.strftime(dtparse(start), format=tmfmt)
this will help The problem is that you are doing setDate() and passing in a dateTime (which then results in the "T15:58:06.165" appended to your date). You can either do EventDateTime().setDateTime() if you want a timed event or if not, you can do something like: new EventDateTime().setDate(new DateTime(true, new Date(), 0));
Wrong date format when i create an event in google calendar
will help you Ok, got it ! The problem was from the google form addon "Form publisher". Ive add an extra date field in my form for testing. In the form editor, the date format showed by google is the right one, but when i explore the template option of Form publisher, the format was named with wrong format.